Transrectal ultrasonic diagnosis of ovarian follicular cysts in goats and treatment with GnRH

Cystic ovarian disease is an important cause of reproductive failure. The objective of this study was to evaluate transrectal ultrasonography as a diagnostic tool and gonadotropin-releasing hormone (GnRH) as a therapeutic approach for ovarian follicular cysts in goats. Goats were considered to have a follicular cyst(s) if a non-echoic structure >10 mm in diameter was detected in the absence of corpora lutea (CL) in three ultrasonic examinations performed at 5-day intervals. After diagnosis (Day 0), goats with ovarian follicular cysts ( n=5) were treated with a single bolus injection of 10.5 μg synthetic GnRH followed by administration of 125 μg prostaglandin F2α (PGF2α) 10 days later. Five blood samples were collected at 5-day intervals for determination of progesterone and estradiol-17β. For detection of LH surge, blood samples were collected every 2 h. Ovulation rate was determined and pregnancy was confirmed by transrectal ultrasonography. The results showed that transrectal ultrasonography is reliable for diagnosis of ovarian follicular cysts and the mean diameter of the follicular cysts was 12.6±0.4 mm. Plasma concentrations of progesterone and estradiol-17β at the time of diagnosis of follicular cysts (Day 0) were 0.7±0.2 ng/ml and 12.7±0.9 pg/ml, respectively. The concentration of progesterone increased to 4.0±0.5 ng/ml 10 days after administration of GnRH indicating luteinization of the ovarian follicular cysts concomitant with a decrease in the concentration of estradiol-17β (3.5±0.4 pg/ml). Administration of GnRH to cystic goats resulted in a surge of LH within 2 h of treatment. The interval from PGF2α injection to the preovulatory LH surge was 62.8±1.4 h. All goats exhibited estrus 55.2±2.3 h after PGF2α injection and four goats out of the five ovulated. The ovulation rate was 1.5±0.3. In conclusion, results of this study suggest that transrectal ultrasonography is a reliable tool for diagnosis of ovarian follicular cysts. In addition, GnRH can be used to effectively treat ovarian follicular cysts in goats with 80% success rate.